The address of the Gorham Macbane Public Library is: 405 White Street, Springfield, 37172 2340
The address of the Robertson County History Museum is: 124 6Th Ave W, Springfield, TN 37172
The address of the Robertson County Historical Society is: Po Box 1022, Springfield, TN 37172-1022
The address of the Coopertown Commission For Culture History And Art is: 2525 Burgess Gower Rd, Springfield, TN 37172-6085
If the barrel has "IMP. CYL." stamped on the barrel near the breech, then the barrel was originally 26" or 28" long, and has been cut If only "CYL." is stamped on the barrel, then it is a riot model and the barrel should be 20" long. I have seen Model 25 Winchester riot guns in the same serial number range that were reportedly used by the Tennessee State Police/Highway Patrol. This claim(s) has not been verified to my knowledge. If it is an original Model 25 Winchester riot shotgun, the fact that you live in Tennessee and got it in Tennessee lends credence to the possibility that it was used by the Tennessee State Police/Highway Patrol. And the fact it is in excellent condition could possibly mean it was used, but very little, by a law enforcement agency. The serial number listed in the question would suggest that the gun was manufactured in 1950 or 1951.